Interpretive Summary: It is critical to conservation professionals to know whether a change in soil and water conservation practices is needed under projected climate change and what practices should be implemented if a change is warranted. An international cooperative research project was initiated in 2005 to (i) develop an innovative spatial and temporal downscaling method that can be used to evaluate farm-specific impacts of projected climate change on water resources, soil erosion, and crop production, and (ii) conduct the impact assessment in southern Loess Plateau of China. A novel spatiotemporal downscaling method was developed and used in this work. Preliminary results simulated at Changwu in southern Loess Plateau using the Soil Erosion Prediction Project (WEPP) model showed that compared with the present baseline climate, the surface runoff and soil erosion under conventional tillage would increase considerably during 2010-2039 under selected climate change scenarios projected by the Hadley Centre’s Global Climate Model. However, the percent increases in both runoff and soil loss were much greater with the spatial downscaling than those without a spatial downscaling. The reason is that the proper treatment of spatial climate variability in the new downscaling method increased the likelihood of occurrence of extreme storm events. Results also indicated that soil erosion than runoff is more sensitive to climate change. More importantly, soil erosion was reduced by more than 85% during 2010-2039 when no-till is used, compared to conventional tillage systems. The information will be useful to scientists and extension specialists for more accurate assessment of soil erosion and for better conservation planning in particular farms under climate change.

Technical Abstract:
An international cooperative research project was initiated in 2005 between the ARS Grazinglands Research Laboratory and the Institute of Soil and Water Conservation, Yangling, Chinese Academy of Sciences. The main goals of the project are to (i) develop an innovative spatial and temporal downscaling method that can be used to evaluate farm-specific impacts of projected climate change on water resources, soil erosion, and crop production, and (ii) evaluate the potential impact of climate change on soil erosion and crop production in southern Loess Plateau of China. The climate change scenarios used in the study were A2a, B2a, and GGa1, which were projected by the Hadley Centre’s Global Climate Model under the forcing of the greenhouse gases emissions scenarios of A2, B2, and GGa reported by the Intergovernmental Panel on Climate Change. A novel spatiotemporal downscaling method was developed and used in the simulation. Preliminary results simulated at Changwu in southern Loess Plateau using the Soil Erosion Prediction Project (WEPP) model showed that compared with the present baseline climate, the surface runoff and soil erosion under conventional tillage would increase considerably during 2010-2039 under the climate change scenarios. However, the percent increases in both runoff and soil loss were much greater with the spatial downscaling than those without a spatial downscaling. The reason is that spatial variability of the climate change scenarios was explicitly considered in the new downscaling method, and such spatial treatment increased the likelihood of occurrence of extreme storm events. Results also indicated that soil erosion than runoff is more sensitive to climate change. More importantly, soil erosion under no-till, compared to conventional tillage, was reduced by more than 85% during 2010-2039.